The present invention is directed to a coiled tubing concentric gas lift assembly which is tubing retrievable, flexible, spoolable and provides a bore therethrough allowing passage of well tools.
It is known, as disclosed in U.S. Pat. No. 5,170,815 to provide removable and flexible gas lift valves internally mounted in a coiled tubing. It is also known, as disclosed in patent application Ser. No. 08/112,038, filed Aug. 26, 1993, U.S. Pat. No. 5,427,133, entitled "Coiled Tubing Wireline Retrievable and Selective Set Gas Lift Assembly", to provide a flexible gas lift valve in a coiled tubing which can be installed and removed by wireline for allowing the passage of other well tools through the coiled tubing.
The present invention is directed to a flexible gas lift valve assembly in a coiled tubing which is positioned concentrically in the coiled tubing to provide an open bore coaxially therethrough which is in communication with the bore of the coiled tubing thereby allowing wireline work to be performed through the gas lift valves, such as bottom hole surveys including pressure and temperature measurements, without removing the gas lift valves. The present invention also provides gas lift valves in which the coaction between the valve element and valve seat is guided and supported and in which the gas lift valves may include injection ports if desired.